Why does it fail?

I'm trying to learn some c++ and it is sometimes very frustrating :(
Can somebody help me to explain whats wrong with the line "cout << p
<< endl;", since it does't print anything.  Everything else works as
expected.  Thanks :)

#include "stdafx.h"
#include <iostream>
#include <bitset>

using namespace std;
int x;
int _tmain(int argc, _TCHAR* argv[])
{
	bitset<12> bs(64);
	const char* p = bs.to_string().c_str();
	const char* c = "kakespade";
	cout << bs.to_string() << endl;
	cout << bs.to_string().c_str() << endl;
	cout << p << endl;
	cout << c << endl;
	cin >> x;
	return 0;
}